The invention relates to devices and systems that deposit small quantities of fluid upon substrates in a precise manner and in arrays of desired density and consistency, and especially to cleaning such systems and other equipment in the laboratory. The invention is useful, for instance, in preventing cross-contamination when carrying out reactions, in providing accurate overlays of deposits, and, in particular, in preparing microscope slides and membranes with biological materials, for instance, microarrays for drug delivery, gene research and clinical use.
In well developed biological analytical technology, and in recently developed xe2x80x9cLab on a Chipxe2x80x9d or biochip technology, creation of dense arrays of fluorescently labeled micro-organisms and DNA assays in a two dimensional field is performed. It is desirable to place the arrays on a conventional microscope slide, or other carrier and to create many such slides simultaneously in a manufacturing process, while it is important to avoid contamination in progressing from work with one material to another.
For biochip technology to proceed to complete fruition, as well as to improve the application of previous analytical techniques, economical instruments and systems have been needed that can, without contamination, rapidly and accurately create the dense array of objects over a large field portion of a glass microscope slide or a slide-like member that occupies an area approximately 22 mm wide and 50 mm long of a slide that is nominally 25 mmxc3x9775 mm.
In the deposition upon a microscope slide of discrete, minute quantities of a large variety of fluid materials, the volume deposited at a discrete spot typically may be from a few pico liter to a fraction of a micro liter, depending upon the application. The devices for forming such deposits are small and can be hard to clean. The biological material carried in this fluid can range from a few strands of short oligonucleotides in a water solution to a high concentration of long strands of complex proteins. The properties of these fluids vary enormously. Some are akin to water while others are far more viscous, resembling a light oil or honey. The range of fluids that may be employed also exhibits wide differences in other properties that make clean up difficult.
Such a large range of property variations in fluids of interest has caused difficulties for any single type of process to operate over a wide range to produce the desired array of deposits, and to maintain such instrument clean and avoid contamination of the procedure.
One purpose of the invention is to provide a technology adapted to the deposition of very small drops of fluids, e.g. drops that form spots of less than about 375 or 300 xcexcm diameter, and in important cases, very much smaller than that, and at correspondingly high densities. (As used in this application, the term fluid xe2x80x9cdropxe2x80x9d refers to a very small quantity of fluid, and not to any particular shape of the fluid volume). The fluids and the resultant dots permissibly exhibit a wide range of properties such as viscosity, evaporative characteristics, surface tension, wettability, surfactant characteristic, dynamic contact angle and free surface energy. These and numerous other objectives are achieved by a number of broad features and preferred embodiments which are individually novel and important and which in many cases cooperate in novel ways to achieve highly effective results.
According to one aspect of the invention, an apparatus for depositing fluid dots on a receiving surface in an array suitable e.g., for microscopic analysis reaction and the like, is provided, comprising a deposit device and a fluid source which are cooperatively related to enable the deposit device to precisely size a drop of fluid of small diameter on a drop-carrying surface of the device, transport mechanism for positioning the device at a precisely referenced lateral position over the receiving surface and drive mechanism for moving the deposit device, relatively, in deposition motion toward and away from the surface, the apparatus adapted, by repeated action, to deposit the drops of fluid precisely in a desired array, and then to proceed to a cleaning station where the instrument is cleaned and then to a resupply station for further action with regard to other materials, free of contamination, preferably the apparatus being computer controlled.
Preferred embodiments have one or more of the following features.
A cleaning station comprises a fluid jet arranged to blow down along the length of the deposit device toward its drop-depositing end, the jet and device being within a confinement chamber.
The deposit device is a pin or pin-like structure having an end surface that carries the fluid drop, preferably the pin or pin-like structure having sides that intersect with the end surface to define a sharp peripheral drop-defining rim.
Another broad aspect of the invention is an apparatus for depositing fluid drops on a receiving surface per se, comprising a deposit device and a fluid source which are cooperatively related to provide to a drop-carrying surface of the deposit device a precisely sized drop of fluid, and a cleaning system that effectively cleans the pin, the deposit device being a pin or pin-like structure having an end surface that serves as the drop-carrying surface, the pin or pin-like structure having sides that intersect with the end surface to define a sharp peripheral drop-defining rim.
Preferred pins or pin-like structures have an end surface that is generally flat and side surfaces that are cylindrical and smooth.
In many important cases, the fluid source is a mobile fluid storage device that is movable relative to an array of deposit locations, the fluid storage device being constructed and arranged to resupply the deposit device at various locations along the array.
Another broad aspect of the invention is an apparatus for depositing fluid drops on a receiving surface, comprising a deposit device and a fluid source which are cooperatively related to provide to the deposit device a drop of fluid, transport mechanism for positioning the deposit device over a receiving surface and drive mechanism for moving the deposit device, relatively, in deposition motion toward and away from the receiving surface, the apparatus adapted, by repeated action, to deposit the drops of fluid in a desired array, the fluid source being a mobile fluid storage device that is movable relative to the array of deposit locations, the fluid storage device being constructed and arranged to resupply the deposit device at various locations along the array, the system adapted to effectively clean the instruments between changes of fluids.
In preferred embodiments employing a mobile storage device, the deposit device and the mobile storage device are constructed to supply drops to the deposit device in the immediate vicinity of the deposit locations for respective drops, preferably the mobile fluid storage device and the deposit device being coupled for transverse motion relative to the array and decoupled for movement of the deposit device toward and away from the receiving surface.
In many cases the mobile storage devices are preferably constructed and arranged to be replenished from a remotely located large reservoir.
In many cases a mobile storage device holds a volume of fluid having a free surface into which the deposit device is lowered and raised to obtain a fluid drop, preferably the mobile storage device being constructed to store a multiplicity of isolated fluid volumes in the wells of a multiwell plate, the apparatus constructed to obtain its fluid from a selected volume of the plate.
In other important cases a mobile storage device defines a generally annular fluid retention surface or ring (the term xe2x80x9cannularxe2x80x9d or xe2x80x9cringxe2x80x9d being used to refer broadly to a member that has opposed, or adjacent, surfaces that can hold a mass of fluid between them by surface tension effects, accessible to a deposit device), and the deposit device is constructed to move within the annular retention surface from retracted to extended positions, in the retracted position the drop-carrying surface of the deposit device being retracted from the surface of fluid retained by the annular surface of the storage device, and in the extended position the drop-carrying surface of the deposit device being projected through and beyond the surface of the retained fluid. Advantageously, the cleaning system cleans the pin and ring simultaneously.
Another broad aspect of the invention is an apparatus for depositing fluid drops on a receiving surface in an array suitable for microscopic analysis, comprising a deposit device and a fluid source which are cooperatively related to provide to a drop-carrying surface of the deposit device a precisely sized drop, and a drive mechanism for moving the deposit device, relatively, in deposition motion toward and away from the receiving surface, the storage device defining a generally annular fluid retention surface, and the deposit device being constructed to move within the annular retention surface from retracted to extended positions, in the retracted position the drop-carrying surface of the deposit device being retracted from the surface of the fluid retained by the annular surface of the storage device, and in the extended position the drop-carrying surface of the deposit device being projected through and beyond the surface of the retained fluid, the relative position of the deposit device and the storage surface being adjustable so that at the cleaning station an optimal relationship for cleaning can be achieved.
In preferred embodiments, a member that defines an annular fluid retention surface is associated with a driver that moves the member relative to the deposit device to a replenishment volume in which the member is immersed to receive a supply of fluid, and to a cleaning position when the system arrives at the cleaning station.
In certain preferred embodiments the deposit device is a pin or pin-like structure e.g. having one or more of the features described above, the pin or pin-like structure being mounted within the confines of an annular fluid retention surface and arranged to move axially relative thereto.
The apparatus of any of the aspects and preferred embodiments described preferably include a control system adapted to control relative movement of the deposit device to a depositing relationship to the receiving surface and a cleaning relationship to the cleaning system.
Another broad aspect of the invention is an apparatus for depositing an array of dots on a receiving surface, comprising a deposit device in the form of a pin or pin-like structure having an end surface capable of precisely defining a small drop of fluid, a source of fluid for the deposit device, mechanism for moving the deposit device relatively over an array of spaced apart deposit locations of a receiving surface, mechanism for repeatedly moving the deposit device, relatively toward and away from the receiving surface to deposit respective drops of fluid at selected deposit locations, a cleaning system, and a control system adapted to control relative movement of the deposit device between a resupply relationship to the source, a depositing relationship to the substrate and a cleaning relationship to the cleaning system.
In embodiments in which the deposit device is associated with a mobile supply device that travels with it, the deposit device and mobile supply device are preferably movable together to the cleaning system in response to the control system, preferably the mobile supply device being an annular member through which the deposit device operates. Preferably the cleaning system has a nozzle for directing a flow of air past the annular structure, preferably a cleaning or drying station comprising a circular nozzle is constructed to discharge a conical flow of fluid, preferably compressed air, high pressure liquid, an aerosol or heated air against a deposit device or mobile fluid source, preferably the deposit device being a pin or pin-like structure surrounded by a mobile reservoir in the form of an annular member capable of holding a supply of fluid by surface tension effects, the nozzle flows directed to dislodge retained fluid, to clean or to dry the respective parts; in some cases, preferably a circular storage device is associated with a heater, e.g., an induction heater.
Preferably, each device to be cleaned has its own cleaning chamber to which it travels, for removal of previous fluid, washing and drying in a so-called xe2x80x9cone stop shopxe2x80x9d.
In certain preferred embodiments of the various aspects and features described, there are provided a set of at least two of the deposit devices, preferably many more, at least one fluid source for providing a drop of fluid on each deposit device, and mechanism for moving the pins together transversely over an array of spaced apart deposit locations of the receiving surface, and to a cleaning station for the respective deposit devices, preferably there being at least four of the deposit devices comprising a deposit head. Preferably the apparatus includes mechanism for repeatedly moving each deposit device independently, or mechanism for moving each deposit device simultaneously, relatively, toward and away from the supply device for resupply, the receiving surface to deposit respective drops at respective deposit locations on the receiving surface, and, optimally the cleaning station.
For simultaneous actuation, preferably two or more deposit devices are mounted on a common support, driven by a common driver to deposit respective fluid drops on the receiving surface. In cases in which each deposit device is associated with a respective storage ring, the storage rings are also mounted on a common support, driven by a common drive; preferably the spacing of the rings corresponds to the spacing of a multiwell storage plate into which the rings are immersed for resupply. In cases in which the deposit device is lowered directly into fluid and raised to obtain its drop, preferably the spacing of the deposit devices corresponds to the spacing of wells of a predetermined multiwell plate, the multiwell plate being a mobile fluid supply that is constructed to accompany the deposit device across the substrate. In the case of supply rings or direct dipping of the deposit devices, preferably the spacing corresponds to well-to-well spacing of wells of a 96, 384, 864 or 1536 well plate, or a spacing of 9 mm or a submultiple of 9 mm. Likewise in this case and others, the deposit devices register with discrete cleaning stations for the individual elements, in which preferably, high speed fluid flow is directed toward the instruments being cleaned, but in a direction away from the work environment. Preferably, the high speed flow induces air flow from the work environment along the device being cleaned to create a negative pressure condition in the work environment and avoid backflow of contaminants from the containment chamber.
The apparatus of any of the foregoing is preferably constructed to mount a number of microscope slides or slide-like structures to serve as the receiving surface, and a control system is constructed and arranged to deposit drops of fluid in selected locations on the slides or slide-like structures, preferably the fluid source comprising a source of biological fluid.
Preferably, for depositing fluid drops in a dense array of mutually isolated dots, a deposit assembly is constructed to travel to a cleaning station, and comprises a fluid source for repeatedly providing a discrete drop of fluid on the tip of the deposit device, mechanism for moving the device relatively over an array of spaced apart deposit locations of a receiving surface, mechanism for repeatedly moving the device, relatively, toward and away from the receiving surfaces to deposit respective dots at respective deposit locations on the surface, preferably the fluid source being a mobile fluid storage device separate from the deposit device, which is generally movable over the array of deposit locations, the fluid storage device being constructed and arranged to resupply the deposit device at various locations with respect to the array.
In certain preferred embodiments of this aspect also, the deposit device is a slidable pin or pin-like structure constructed and arranged to dip into a volume of fluid carried by a mobile storage device, preferably the storage device being constructed to store a multiplicity of isolated fluid volumes, the apparatus constructed to move the supply device relative to the deposit device to select the fluid to be deposited, preferably the storage device being a 96 well plate or a plate having a multiple of 96 wells, and also preferably including at least one driven stage for moving a selected well of a mobile multiwell plate into registry with the deposit device under computer control for enabling motion of the deposit device to dip into and out of the preselected well to provide a drop of the selected fluid to the device.
In other preferred embodiments the mobile storage device is an annular ring as described above.
Another broad aspect of the invention is a deposit apparatus comprising a multiplicity of deposit devices as described, mounted for motion together in response to a common actuator, preferably the deposit devices comprising deposit pins or pin-like structures adapted to enter respective cells of a cleaning station of the kind described above.
Another broad aspect of the invention is an apparatus comprising a mobile fluid storage device separate from a deposit device and generally movable over an array of deposit locations, the fluid storage device being constructed and arranged to resupply the deposit device at various locations with respect to the array, in one case, preferably the mobile fluid storage device being constructed to store a multiplicity of isolated fluid volumes, the apparatus constructed to move the mobile storage device relative to the deposit device to select the fluid to be deposited, preferably the deposit device being a pin or pin-like structure constructed and arranged, under computer control, to dip into a cleaning station periodically and in operation, dip into a selected volume of fluid carried by the mobile fluid storage device, preferably the mobile fluid storage device being a multiwell plate having 96 wells or multiples of 96 wells, or a spacing of 9 mm or a submultiple of 9 mm and preferably the apparatus including a driven stage for moving the fluid storage device into registry with the deposit device under computer control for enabling dipping of the deposit device into a preselected fluid volume; in another case preferably the mobile storage device is an annular ring that retains a supply of fluid by surface tension.
The invention also features the method of use of all the described apparatus in depositing fluid drops, especially the fluids mentioned in the specification, and in subsequent cleaning.
In the various methods, preferably the receiving surface is fragile, or soft, preferably the receiving surface is porous or microporous or fibrous, preferably comprising nitrocellulose, nylon cellulose acetate or polyvinylidine fluoride or a gel, preferably the member defining the soft or fragile receiving surface being mounted on a rigid carrier member, either directly or upon an intermediate soft or resilient buffer member.
Preferably the method is employed to deposit a fluid selected from the group of biological fluids described in the specification, preferably the material being a biological probe or a chemical for reaction with biological material, a fluorescing material, an ink, dye, stain or marker, a photoactive material, or a varnish or an encapsulant or an etchant, or a cleaning or neutralizing agent.
Another broad aspect of the invention is the method of depositing a biological fluid with a pin or pin-like structure comprising supporting fluid within a ring by surface tension, and moving the pin or pin-like structure through the ring in the manner that a relatively small drop of the fluid is held at the end of the pin by surface tension and deposited on a receiving surface, and moving the ring to a cleaning station prior to resupply.